On Dec 30, 2009, at 4:10 AM, Steve Holden wrote:
Roald de Vries wrote:
On Dec 30, 2009, at 2:28 AM, Dave Angel wrote:
Roald de Vries wrote:
On Dec 29, 2009, at 8:34 PM, Dave Angel wrote:
Antoine Pitrou wrote:
Le Tue, 29 Dec 2009 16:09:58 +0100, Roald de Vries a écrit :
Dear all,
Is it possible for a Python script to detect whether it is
running
interactively? It can be useful for e.g. defining functions
that are
only useful in interactive mode.
Try the isatty() method (*) on e.g. stdin:
$ python -c "import sys; print sys.stdin.isatty()"
True
$ echo "" | python -c "import sys; print sys.stdin.isatty()"
False
Your test determines whether input is redirected. But I think the
OP was asking how to detect whether the script was being run
from an
interpreter prompt.
That was my question indeed. Is it possible?
If I had had a good answer, I would have supplied it in my earlier
message.
The sneaky answer would be that a script cannot be used
interactively,
as once you import it from the interpreter, it's a module, not a
script. So you can detect that it's not a script, by examing
__name__
in the usual way. If it's a script, it'll have a value of
"__main__".
But that won't tell you if you're running inside an IDE, or using
the
-i switch on the Python command line, or probably a bunch of other
questions. I don't know of any "correct" answer, and I'm not sure
what the real use case is for knowing. Are you really going to
somehow define a different set of functions???
I'm using a database, and want to use python interactively to
manipulate
it. On the other hand, I also want to be able to use it
non-interactively. In that case, it would be a waste of CPU to load
the
function/class definitions meant for interactive use.
This is an extreme case of premature optimization. Write the code and
run it. Do you have any idea how much extra time and memory loading
the
additional code will require? If not, it's a waste of your time to
even
think about omitting the stuff required for interactive use.
Once you get a handle on the structures and functions required for
interactive vs. non-interactive use you can consider refactoring the
code so that the non-interactive programs don't need to import the
stuff
that's exclusively for interactive use. But frankly I wouldn't waste
your time.
Actually, performance is not much if an issue for what I want to do;
it's mainly interest in 'how should I do this in general'. I'll just
leave in all the code, and if it becomes a real issue, I'll separate
the code over an interactive and a non-interactive script. Thanks for
your inputs.
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